JP2004207608A - Laminated electronic component and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide laminated electronic components having uniform characteristics and built-in coils with improved a Q value and a method for manufacturing the laminated electronic components. <P>SOLUTION: A plurality of coil forming recessed grooves 2 are aligned and worked on a green sheet 1 and conductive paste 3 for forming coils is printed in each recessed groove 2. Then a plurality of green sheets 1 are laminated, a plurality of coils are formed in the laminated green sheets 1, the laminated green sheets 1 are cut off and sintered, and thermal electrodes are formed on both the ends of the cut sheets 1. A part of a coil conductor is partrally overlapped on both the sides of each recessed groove 2 in the cross-sectional shape after sintering the coil. The aspect ratio t/w of thickness (t) to width (w) of a cross section of the coil conductor is 0.7 and more. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multilayer electronic component or a multilayer coil manufactured by processing a concave groove for forming a coil on a green sheet, printing a conductive paste, laminating a plurality of the sheets, crimping, cutting, and firing. And a method of manufacturing the same.
[0002]
[Prior art]
Conventional multilayer electronic components, such as inductors with coils inside, use a green sheet made of a magnetic or non-magnetic material with through-holes formed by screen printing conductive paste to form a large number of coil conductors. It is manufactured by forming a coil, forming a coil by laminating a plurality of green sheets, cutting and firing, and forming a terminal electrode. FIG. 9 (A) shows an example thereof, 20 is a body formed by laminating green sheets, 21 is a coil, and 22 is a terminal electrode in which both ends of the coil 21 are connected by conductors in through holes (not shown). It is.
[0003]
In such a multilayer electronic component, as shown in FIG. 9C, in order to increase the cross-sectional area of the coil 23 to lower the DC resistance value and increase the Q value as shown in FIG. A groove 25 is formed in the green sheet 24, and the conductive paste 23 is printed in the groove 25 to form a coil conductor (for example, see Patent Document 1). When the cross-sectional area of the coil 23 is increased in this way, as shown in FIG. 10, the laminated type electron with a lower direct current resistance (RDC) is obtained as shown in FIG. Parts are obtained.
[0004]
[Patent Document 1]
JP-A-3-219605.
[0005]
[Problems to be solved by the invention]
In the multilayer electronic component having the configuration described in Patent Document 1 or the like, as shown in FIG. 9C, the conductive paste 23 is set to have the same width with respect to the groove 25 of the green sheet 24. When the conductive paste 23 is displaced with respect to the concave groove 25 because of the application, a gap is easily generated inside the element body 20 due to the presence of the concave groove 25, and there is a problem that the characteristics vary. Further, even if the cross-sectional area of the coil 23 increases and the DC resistance value decreases, the Q value can be improved if the distance D between the opposed inner sides and the distance C between the outer sides of the coils 21 and 23 are the same. There is a problem that can not be.
[0006]
The present invention has been made in view of the above-described problems of the prior art, and has as its object to provide a multilayer electronic component with a built-in coil having uniform characteristics and a method of manufacturing the same. Another object of the present invention is to provide a multilayer electronic component capable of improving the Q value and a method of manufacturing the same.
[0007]
[Means for Solving the Problems]
(1) In the laminated electronic component of the present invention, a concave is formed in a green sheet, a plurality of conductive pastes are vertically and horizontally printed in the concave, and a plurality of green sheets are laminated to form a plurality of inside. A laminated electronic component manufactured by forming a coil of, cutting, firing, and providing terminal electrodes at both ends,
In the coil conductor formed of the conductive paste, in the cross-sectional shape after firing, a part of the coil conductor overlaps both sides of the concave groove, and an aspect ratio between a thickness t and a width w of a cross section of the coil conductor. It is characterized in that t / w is 0.7 or more.
[0008]
(2) In the multilayer electronic component of the present invention,
The aspect ratio is preferably 0.7 to 1.1.
[0009]
(3) In the multilayer electronic component of the present invention,
Preferably, the cross-sectional shape of the coil conductor is substantially circular.
[0010]
(4) In the method of manufacturing a laminated electronic component according to the present invention, a groove is formed in a green sheet, a plurality of conductive pastes are vertically and horizontally printed in the groove, and a plurality of green sheets are laminated. A method for manufacturing a multilayer electronic component manufactured by forming a plurality of coils inside, cutting and firing, and providing terminal electrodes at both ends,
A step of irradiating a laser beam on the surface of the ceramic green sheet attached to the base film to form a groove,
In the groove, a step of printing a conductive paste wider than the groove,
Laminating a green sheet including a plurality of green sheets printed with a conductive paste, pressure bonding, cutting and firing each step,
A conductive paste is printed in the concave groove of the green sheet so that the aspect ratio b / a of the thickness b and the width a is 0.78 or more.
[0011]
(5) In the method for manufacturing a multilayer electronic component of the present invention,
It is preferable that the conductive paste is printed so that the depth d of the conductive paste in the concave groove of the green sheet is substantially equal to the dimension c of the conductive paste rising from the surface of the green sheet.
[0012]
(6) In the method for manufacturing a multilayer electronic component of the present invention,
When printing a conductive paste on the green sheet, it is preferable to print the conductive paste with a width a of 1.2 times or more the width e of the concave groove.
[0013]
(7) In the method for manufacturing a multilayer electronic component of the present invention,
It is preferable that the groove is formed in the V-shaped cross-section at a depth that does not reach the base film in the green sheet attached to the base film.
[0014]
(8) In the method for manufacturing a multilayer electronic component of the present invention,
It is preferable that the concave groove in the green sheet is formed by a carbon dioxide laser.
[0015]
(9) In the method for manufacturing a multilayer electronic component of the present invention,
Before or after processing the plurality of grooves in the green sheet vertically and horizontally by laser light, it is preferable to adjust the laser output to process all the through holes to be processed on the entire surface of the green sheet.
[0016]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a layer structure diagram showing one embodiment of a laminated electronic component according to the present invention, and FIG. 1B is an external view thereof. 1a to 1n are insulating layers made of a magnetic or non-magnetic material, 2a to 2h are concave grooves formed in the insulating layers 1c to 1j, 4a to 4n are through holes provided in the insulating layers 1a to 1n, respectively. Reference numerals 3a to 3n denote conductors that fill the through holes 4a to 4n and fill the concave grooves 2a to 2i for 3c to 3j, respectively, and form a coil 12 (see FIG. 6B) described later. And conductors 3a, 3b, 3k, and 3n for connecting the coil 12 to the terminal electrodes 11 (see FIGS. 1B and 6B) described later.
[0017]
In FIG. 1B, reference numeral 10 denotes a body composed of a stack of insulator layers 1a to 1n provided with conductors 3a to 3n, and 11 denotes terminal electrodes provided at both ends thereof.
[0018]
FIG. 2 is a layer structure diagram showing a laminated structure in actual production of this laminated electronic component, wherein 1a to 1n are green sheets for realizing the insulator layers 1a to 1n shown in FIG. In order to obtain a plurality of laminated electronic components, a plurality of the concave grooves 2a to 2h, through holes 4a to 4n, and conductors 3a to 3n are provided on each green sheet vertically and horizontally. Reference numeral 5 denotes a cutting mark provided on the end 1n of the green sheets to be laminated, and reference numeral 6 denotes a cutting line.
[0019]
The green sheets 1a to 1n shown in FIG. 2 are laminated by a conventional method as shown in FIG. 3, cut along a cutting line 6, and provided with the terminal electrodes 11 after firing. The terminal electrode 11 is formed by baking a conductive paste containing silver or the like as a main component and, for example, Ni plating and Sn plating. The plating of the terminal electrode 11 may be performed by plating of Cu and Ni and Sn, plating of Ni and Au, plating of Ni and Ag, or the like.
[0020]
FIG. 4 shows an embodiment of the method of manufacturing the multilayer electronic component according to the present invention for a part of one coil. 4A is a plan view thereof, and FIGS. 4B and 4C are a YY sectional view and an XX sectional view of FIG. 4A, respectively.
[0021]
In FIG. 4, 1 is a green sheet, 2 is a groove formed on one side of the green sheet 1, 4 is a through hole provided through the green sheet 1 at an end thereof, and 3 is printed along the groove 2. And a conductive paste for forming a coil conductor filled in the through hole 4.
[0022]
As shown in FIGS. 4D and 4E, the green sheet 1 is formed by applying a ceramic paste on a base film 7 made of a PET film by a doctor blade method or the like. It is formed by irradiating a laser beam with a carbon dioxide gas laser or the like in a state where the base film 7 is attached to the green sheet 1. Here, the through hole 4 is formed at a depth from the surface of the green sheet 1 to the base film 7 through the green sheet 1, and the concave groove 2 is formed at a depth not reaching the base film 3.
[0023]
In this case, as shown in FIG. 5 (A), the laser output is reduced after the plurality of grooves 2 are formed in a single green sheet 1 in a longitudinally and horizontally aligned manner or before the through holes 4 are formed. It is formed by adjusting the height higher than in the case of and irradiating a laser beam to a portion corresponding to the end of the concave groove 2. After the grooves 2 and the through holes 4 are provided in this way, as shown in FIG. 5B, the conductive paste 3 is printed by screen printing or the like.
[0024]
When printing the conductive paste 3, as shown in FIG. 4C, the width a of the conductive paste 3 to be printed is set to be larger (a> e) than the width e of the groove 2. Preferably, the width a of the conductive paste 3 is set to be at least 1.2 times the width e of the groove 2.
[0025]
If the width a of the conductive paste 3 is set to be wider than the width e of the groove 2 in this manner, the entire groove 2 can be covered with the conductive paste 3 even when the printing accuracy of the conductive paste 3 is somewhat poor. , It is possible to prevent the generation of voids, and to reduce the variation in characteristics.
[0026]
Further, by setting the aspect ratio r = b / a between the thickness b and the width a of the conductor layer in the groove 2 to 0.78 or more, the conventional product shown in FIG. 6B), a coil 12 having a smaller width a can be obtained. Here, in order to maximize the cross-sectional area of the coil and to prevent the formation of a gap between the coil and the insulator layer, it is preferable that the cross-sectional shape be circular or nearly circular. The groove 2 is preferably V-shaped as shown.
[0027]
In order to easily form the conductive paste 3 having a large cross-sectional area and print the conductive paste 3 in a cross-sectional shape close to a circle, the depth d of the conductive paste 3 in the concave groove 2 in a green sheet state is required. It is preferable that the depth and the screen of the concave groove 2 are set so that the height c of the conductive paste 3 from the surface of the green sheet 1 is substantially equal to that of the conductive paste 3.
[0028]
The aspect ratio of the conductive paste 3 is more preferably 0.78 to 1.16. When the aspect ratio exceeds 1.16, the printability of the conductive paste tends to decrease.
[0029]
Since the coil conductor is compressed in the laminating direction by laminating, pressing, and firing the green sheets, the aspect ratio r = 0.78 in the green sheet state is 0.7 after firing. Further, a preferable aspect ratio of 0.78 to 1.16 corresponds to an aspect ratio of 0.7 to 1.1 after firing.
[0030]
EXAMPLE A green sheet 1 containing ceramic powder of 70% by weight of glass made of strontium, calcium, alumina and silicon oxide and 30% by weight of alumina was used. The thickness of the green sheet 1 was set to 50 μm, and the concave groove 2 was processed by a carbon dioxide laser so that the depth d became 20 μm and the width e became 30 μm. The through hole 4 was formed to have a diameter of about 30 μm.
[0031]
On the other hand, the conductive paste 3 had a width a of 36 μm and a thickness b (= c + d) of 40 μm (ie, c = 20 μm). The conductive paste 3 was mainly composed of silver and formed by screen printing. The dimensions of the prototype were set to 0.5 mm × 0.5 mm in the horizontal and vertical dimensions, and the length in the coil winding direction to 1.0 mm. The number of turns was 7.5. The nominal value of the inductance of this laminated inductor is 12 nH.
[0032]
The width of the coil section after firing of the prototype of this example (the width corresponding to the width a in the green sheet state) was 33 μm, and the aspect ratio was 1.1. Further, the distance D2 between the opposing sides of the coil 12 shown in FIG. 6B was 360 μm.
[0033]
On the other hand, for comparison, as a conventional product, it has the same cross-sectional area as the coil 12 of the embodiment, the number of turns is the same as that of the embodiment, and as shown in FIG. A constraint that the coil 21 (12) should not be exposed from the surface of the element body 20 (10) under the condition that the DC resistance values between the 22 and 22 (conventional products) are equal (interval between the outer sides of the coil). C1 is equal), the distance D1 between the opposing sides of the coil 21 was 300 μm in the conventional product.
[0034]
FIG. 8 shows the results of obtaining the Q value of the prototype according to the embodiment and the conventional product while changing the frequency. As can be seen from FIG. 8, in the range of the measured frequency from 100 MHz to 3 GHz, the product of the example of the present invention showed a significant improvement in Q value as compared with the conventional product.
[0035]
The present invention integrally forms not only an inductor having a structure in which terminal electrodes 11 are provided at both ends in the stacking direction, but also a structure having terminal electrodes at both ends in a direction perpendicular to the stacking direction, and other elements such as a capacitor. Applicable to structures. Further, it is also possible to constitute a module as a laminated structural component integrated with a plurality of elements.
[0036]
【The invention's effect】
According to the present invention, it is possible to provide a multilayer electronic component having uniform characteristics and an improved Q value.
[Brief description of the drawings]
FIG. 1A is a layer structure diagram showing an embodiment of a multilayer electronic component according to the present invention, and FIG. 1B is an external view thereof.
FIG. 2 is a perspective view showing a layer structure in a green sheet state of the present embodiment.
FIG. 3 is a perspective view showing a laminated state of the green sheets of the present embodiment.
FIG. 4A shows an embodiment of a method for manufacturing a multilayer electronic component of the present embodiment for a part of one coil, and FIG. 4A is a plan view thereof, and FIGS. () Is a cross-sectional view taken along the line Y-Y and XX is a cross-sectional view of (A), and (D) and (E) are cross-sectional views illustrating formation of through holes and concave grooves by laser light.
FIG. 5A is a plan view of a green sheet showing a state after processing of a through hole and a concave groove in the present embodiment, and FIG. 5B is a plan view showing a state where a conductive paste is applied thereafter. .
FIG. 6A is a cross-sectional view of a conventional multilayer electronic component, and FIG. 6B is a cross-sectional view showing one embodiment of the multilayer electronic component of the present invention.
FIG. 7 is a diagram showing a comparison between DC resistance values of a conventional multilayer electronic component and a multilayer electronic component of an embodiment of the present invention.
FIG. 8 is a diagram showing Q values of a conventional multilayer electronic component and a multilayer electronic component of an embodiment of the present invention in a predetermined frequency range.
9A is a cross-sectional view of a conventional multilayer electronic component, and FIG. 9B is a cross-sectional view of a conventional multilayer electronic component manufactured using a process of providing a concave groove in a green sheet and embedding a conductive paste. FIG. 3C is a cross-sectional view showing the state of application of the conductive paste in the green sheet state.
FIG. 10 is a diagram showing a comparison of DC resistance values of the multilayer electronic components shown in FIGS. 9A and 9B.
[Explanation of symbols]
1: green sheet, 1a to 1n: insulator layer (green sheet), 2, 2a to 2n: concave groove, 3: conductive paste, 3a to 3n: conductor, 4: through hole, 5: mark, 6: cut Wire, 7: base film, 10: elementary body, 11: terminal electrode, 12: coil

Claims (9)

A concave is formed in the green sheet, a plurality of conductive pastes are vertically and horizontally printed in the concave, a plurality of green sheets are laminated to form a plurality of coils inside, cut, fired, and both ends are cut. A multilayer electronic component manufactured by providing a terminal electrode in a part,
In the coil conductor formed of the conductive paste, in the cross-sectional shape after firing, a part of the coil conductor overlaps both sides of the concave groove, and an aspect ratio between a thickness t and a width w of a cross section of the coil conductor. A laminated electronic component, wherein t / w is 0.7 or more. The multilayer electronic component according to claim 1,
The laminated electronic component, wherein the aspect ratio is 0.7 to 1.1. The multilayer electronic component according to claim 1, wherein
A laminated electronic component, wherein the cross-sectional shape of the coil conductor is substantially circular. A concave is formed in the green sheet, a plurality of conductive pastes are vertically and horizontally printed in the concave, a plurality of green sheets are laminated to form a plurality of coils inside, cut, fired, and both ends are cut. A method for manufacturing a laminated electronic component manufactured by providing a terminal electrode in a portion,
A step of irradiating a laser beam on the surface of the ceramic green sheet attached to the base film to form a groove,
In the groove, a step of printing a conductive paste wider than the groove,
Laminating a green sheet including a plurality of green sheets printed with a conductive paste, pressure bonding, cutting and firing each step,
A method of manufacturing a multilayer electronic component, comprising printing a conductive paste in the concave groove of the green sheet so that an aspect ratio b / a of a thickness b and a width a thereof is 0.78 or more. The method for manufacturing a multilayer electronic component according to claim 4,
Printing a conductive paste such that a depth d of the conductive paste in the concave groove of the green sheet and a swelling dimension c of the conductive paste from the surface of the green sheet are substantially equal. The method of manufacturing the part. The method for manufacturing a multilayer electronic component according to claim 4 or 5,
When printing a conductive paste on the green sheet, the conductive paste is printed with a width a that is at least 1.2 times the width e of the concave groove, and a method of manufacturing a multilayer electronic component. The method for manufacturing a multilayer electronic component according to any one of claims 4 to 6,
A method for manufacturing a laminated electronic component, wherein the groove is formed in a V-shaped cross section at a depth that does not reach the base film in the green sheet attached to the base film. The method for manufacturing a multilayer electronic component according to any one of claims 4 to 7,
A method for manufacturing a laminated electronic component, wherein the concave groove in the green sheet is formed by a carbon dioxide gas laser. The method for manufacturing a multilayer electronic component according to any one of claims 4 to 8,
Before or after processing the plurality of grooves in the green sheet vertically and horizontally by laser light, the laser output is adjusted to process all the through holes to be processed on the entire surface of the green sheet. Manufacturing method of electronic components.

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